updating ispconfig

Hi everybody
I'am new in this forums, thank you all for so much help.
ISPconfig is great and my first question is this:
I read that if a new version of ISPconfig came out and we start the installation script ./setup if the installer detect any existing installation just perform and update.

Is safe to do this in a production server, with users using mail or web pages?.
Is there any special care to do this update?.

In case anything goes wrong, you can restore the backups of the directories /root/ispconfig, /home/admispconfig and the ispconfig database that the installer places in your /tmp directory. If the installation works as expected, dont forget do delete them later.